Much progress in plant improvement has been made by seed propagation involving the repeated process of collecting seeds from plants that look best in a field. However, a conventional seed propagation method has not been successfully applied to vegetatively propagative plants, e.g., garlic. The improvement of such plants has been made by repetitive selection of propagules, which requires a number of years. In addition, the conventional breeding method based on sexual reproduction is restricted only to those between closely related plants, although there are many cases in which seeds cannot be obtained.
Recently, seed propagative garlic has been found and sexual reproduction of seed-fertile clones has become feasible. However, there has been no report on a new cultivar obtained by seed propagation, yet.
On the other hand, a cell fusion technique was developed to bypass "the barrier of seed propagation" which set a limit to the conventional breeding method. Although the cell fusion technique is applicable to hybridization of seed-sterile plants, the technique is known to cause heritable alteration such as changes in chromosome number during plant regeneration. Plants belonging to the genus Allium, such as onion, garlic and Chinese chive are generally difficult to form somatic embryos, and the fused cell is also difficult to regenerate. In addition, it has been reported on the stability of the fused cell that either one of the chromosome sets of the cell is likely to be lost during growing into a plantlet.
There has been no report that the hybrid plants of an onion and a Chinese chive can be made by the conventional crossbreeding method or a cell fusion technique.